// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2015 Benoit Steiner <benoit.steiner.goog@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include "main.h"

#include <Eigen/CXX11/Tensor>

struct Generator1D
{
	Generator1D() {}

	float operator()(const array<Eigen::DenseIndex, 1>& coordinates) const { return coordinates[0]; }
};

template<int DataLayout>
static void
test_1D()
{
	Tensor<float, 1> vec(6);
	Tensor<float, 1> result = vec.generate(Generator1D());

	for (int i = 0; i < 6; ++i) {
		VERIFY_IS_EQUAL(result(i), i);
	}
}

struct Generator2D
{
	Generator2D() {}

	float operator()(const array<Eigen::DenseIndex, 2>& coordinates) const
	{
		return 3 * coordinates[0] + 11 * coordinates[1];
	}
};

template<int DataLayout>
static void
test_2D()
{
	Tensor<float, 2> matrix(512, 512);
	Tensor<float, 2> result = matrix.generate(Generator2D());

	for (int i = 0; i < 512; ++i) {
		for (int j = 0; j < 512; ++j) {
			VERIFY_IS_EQUAL(result(i, j), 3 * i + 11 * j);
		}
	}
}

template<int DataLayout>
static void
test_gaussian()
{
	int rows = 32;
	int cols = 48;
	array<float, 2> means;
	means[0] = rows / 2.0f;
	means[1] = cols / 2.0f;
	array<float, 2> std_devs;
	std_devs[0] = 3.14f;
	std_devs[1] = 2.7f;
	internal::GaussianGenerator<float, Eigen::DenseIndex, 2> gaussian_gen(means, std_devs);

	Tensor<float, 2> matrix(rows, cols);
	Tensor<float, 2> result = matrix.generate(gaussian_gen);

	for (int i = 0; i < rows; ++i) {
		for (int j = 0; j < cols; ++j) {
			float g_rows = powf(rows / 2.0f - i, 2) / (3.14f * 3.14f) * 0.5f;
			float g_cols = powf(cols / 2.0f - j, 2) / (2.7f * 2.7f) * 0.5f;
			float gaussian = expf(-g_rows - g_cols);
			VERIFY_IS_EQUAL(result(i, j), gaussian);
		}
	}
}

EIGEN_DECLARE_TEST(cxx11_tensor_generator)
{
	CALL_SUBTEST(test_1D<ColMajor>());
	CALL_SUBTEST(test_1D<RowMajor>());
	CALL_SUBTEST(test_2D<ColMajor>());
	CALL_SUBTEST(test_2D<RowMajor>());
	CALL_SUBTEST(test_gaussian<ColMajor>());
	CALL_SUBTEST(test_gaussian<RowMajor>());
}
